The method for manufacturing timepiece hairsprings according to the invention comprises the following successive steps: a) forming hairsprings in a wafer, b) forming a thermal compensation layer on the hairsprings, c) identifying the hairsprings having a stiffness within a predetermined range, d) optionally, detaching from the wafer the hairsprings identified in step c), e) modifying the other hairsprings so that the stiffness of at least some of them is within the predetermined range, f) detaching from the wafer these other hairsprings and, if they have not been detached in step d), the hairsprings identified in step c). This method makes it possible to reduce manufacturing dispersions between the hairsprings.

Method for press-rolling a mainspring, from a wire comprising a pre-formed eye, utilising a roller press comprising a first support and guide means exerting a force on the wire in a first contact area located between a second and a third contact area comprised in a second and a third support and guide means, in order to wind, beyond the eye, an accumulation area with an opposite curvature to that of the eye, and wherein, as the wire advances, the position of the first contact area is gradually moved away from the second and third contact areas, to vary the press-rolling radius from a first minimum value to a second maximum value at a neck junction between the accumulation area and the eye.

A method for manufacturing a balance spring intended to equip a balance of a horological movement, including a step of producing a blank made of a Nb—Zr alloy including between 10 and 30 wt % Zr, a step of annealing and cooling the blank, at least one step of deforming the annealed blank in order to form a wire, wherein, before the deformation step, a step of depositing, on the blank, a layer of a ductile material chosen from copper, nickel, cupronickel, cupro-manganese, gold, silver, nickel-phosphorus Ni—P and nickel-boron Ni—B, in order to facilitate the wire shaping operation, the thickness of the ductile material layer deposited being chosen such that the ratio of the area of ductile material to the area of the alloy for a given wire cross-section is less than 1, preferably less than 0.5, and more preferably lies in the range 0.01 to 0.4.

Disclosed is a method including: a) obtaining a substrate extending in a predetermined plane with a first layer parallel to the plane; b) forming a through-hole in the first layer; c) depositing a second layer on the first, the second layer filling the a through-hole to form a bridge of material; d) etching a hairspring in an etching layer made up of the second layer or the substrate, the one of the second layer and the substrate in which the a hairspring is not etched constituting a support, the bridge of material connecting the hairspring to the support perpendicular to the predetermined plane; e) removing the first layer, the hairspring remaining attached to the support by the bridge of material; f) subjecting the hairspring to a thermal treatment; and g) detaching the hairspring from the support.

A balance-spring intended to equip a balance of an horological movement, comprising a core made of Nb—Ti made from an alloy consisting of: niobium: balance to 100% by weight, titanium: between 5 and 95% by weight, traces of elements chosen from the group consisting of O, H, C, Fe, Ta, N, Ni, Si, Cu, Al, each of said elements being present in a quantity between 0 and 1600 ppm by weight, the total quantity formed by all of said elements being between 0% and 0.3% by weight, wherein the core made of Nb—Ti is coated with a layer of niobium, said layer of niobium having a thickness between 20 nm and 10 μm.

The method for manufacturing timepiece hairsprings according to the invention comprises the following successive steps: a) forming hairsprings in a wafer, b) forming a thermal compensation layer on the hairsprings, c) identifying the hairsprings having a stiffness within a predetermined range, d) optionally, detaching from the wafer the hairsprings identified in step c), e) modifying the other hairsprings so that the stiffness of at least some of them is within the predetermined range, f) detaching from the wafer these other hairsprings and, if they have not been detached in step d), the hairsprings identified in step c). This method makes it possible to reduce manufacturing dispersions between the hairsprings.

Disclosed is a method including: a) obtaining a substrate extending in a predetermined plane with a first layer parallel to the plane; b) forming a through-hole in the first layer; c) depositing a second layer on the first, the second layer filling the a through-hole to form a bridge of material; d) etching a hairspring in an etching layer made up of the second layer or the substrate, the one of the second layer and the substrate in which the a hairspring is not etched constituting a support, the bridge of material connecting the hairspring to the support perpendicular to the predetermined plane; e) removing the first layer, the hairspring remaining attached to the support by the bridge of material; f) subjecting the hairspring to a thermal treatment; and g) detaching the hairspring from the support.

A method for manufacturing a balance spring intended to equip a balance of a horological movement, including a step of producing a blank made of a NbZr alloy including between 10 and 30 wt % Zr, a step of annealing and cooling the blank, at least one step of deforming the annealed blank in order to form a wire, wherein, before the deformation step, a step of depositing, on the blank, a layer of a ductile material chosen from copper, nickel, cupronickel, cupro-manganese, gold, silver, nickel-phosphorus NiP and nickel-boron NiB, in order to facilitate the wire shaping operation, the thickness of the ductile material layer deposited being chosen such that the ratio of the area of ductile material to the area of the alloy for a given wire cross-section is less than 1, preferably less than 0.5, and more preferably lies in the range 0.01 to 0.4.

Method for press-rolling a mainspring, from a wire comprising a pre-formed eye, utilizing a roller press comprising a first support and guide means exerting a force on the wire in a first contact area located between a second and a third contact area comprised in a second and a third support and guide means, in order to wind, beyond the eye, an accumulation area with an opposite curvature to that of the eye, and wherein, as the wire advances, the position of the first contact area is gradually moved away from the second and third contact areas, to vary the press-rolling radius from a first minimum value to a second maximum value at a neck junction between the accumulation area and the eye.

The spiral includes turns of rectangular section, whose pitch p and/or thickness e can vary from the inside curve towards the outside curve, or whose winding can deviate from the line of a perfect spiral. The inside curve can also be extended by a self-locking washer for fixing the spiral on the balance arbour with no play. The spiral is manufactured by photolithography and galvanic growth, or by micro-machining an amorphous or crystalline material, such as a silicon wafer.